About Skin Cancer 

Nonmelanoma skin cancers (NMSCs) and melanomas

Skin cancer are mainly found in two types, melanoma and nonmelanoma.

Approximately 4% of new cancer cases in the UK are due to melanomas, the 5th most common form of skin cancer, and there are nearly 430 new cases of non-melanoma skin cancer every day (2016-2018).^1,2

Skin cancers usually appear as lesions that do not heal within four weeks, and are unnatural, itchy, bleed, crusty or scab for more than four weeks. Typically, melanomas can be brown-to-black or vary in colour, have irregular borders, and measure more than 6 mm in diameter.⁵

Causes and risk factors:

• Ultraviolet (UV) solar radiation is the leading cause of melanomas,  especially basal cell carcinoma (BCC) and squamous cell carcinoma SCC).³

• Melanoma risk is directly linked to sun exposure during adolescence, specifically, the number of incidences of sunburn between the ages of 15 and 20.⁴

• Other risk factors involved in the development of carcinomas include the presence of moles (melanocytic nevi), chemical exposure, tanning bed use, human papillomavirus (HPV), Fitzpatrick skin type, and suppression of the immune system.⁴

Treatment Options for Skin Cancer

• Freezing/ cryotherapy:

Cryotherapy, or cryoablation, is based on the principle that extremely cold temperatures can destroy cancer cells.⁶ It is used in basal cell carcinoma, squamous cell carcinoma, actinic keratosis, Kaposi's sarcoma, and Bowen’s disease, among others. This therapy can be provided in three forms: contact, spray and intralesional.

• The contact method is the most commonly used in clinical settings, wherein a cotton swab is used to apply the cryogenic agent to the affected area/lesion.
• With the spray method, the agent is sprayed from a distance of 1-2 cm perpendicular to the lesion. 
• The intralesional method is mainly used in malignant cancers, and it helps the preservation of the epidermis and prevents scarring.

Pain, swelling, redness, blistering, and infection are some of the potential side effects of the above treatments. 

• Excisional Surgery 

Surgical treatment is generally considered the most effective treatment option for non-malignant skin cancers (NMSC), such as basal cell carcinomas and squamous cell carcinomas.⁷ The most common surgical techniques used in NMSC treatment are curettage and electrodesiccation, standard surgical excision, and Mohs micrographic surgery.

A surgical procedure's primary aim is to remove the tumour completely to prevent a recurrence, minimise functional impairment after tumour removal, and optimise cosmetic appearance after the procedure.

Curettage & electrodesiccation tumour destruction is one of the most common and effective treatments for non-melanoma skin cancer.  Techniques vary from one practitioner to another, but conventional tumours are removed with a curette, followed by electrodesiccation of the tissue until the normal dermis can be identified. 

Curettage and electrodesiccation are typically repeated one to three times, but the evidence to support this particular method, including treatment margins, is lacking.

• Mohs surgery 

Mohs surgery, also known as Mohs micrographic surgery, or MMS, is the most effective method for removing cancer while preserving maximum tissue and achieving optimal cosmetic appearance.^8,9 In certain cases, it is used when there is a high risk of recurrence of skin cancer.

Mohs surgery is often also used when there is a desire to preserve as much healthy skin as possible, such as with skin cancers that are near the eye, the central part of the face, the ears, or other critical areas such as the fingers.

Medicine is first injected into the affected area to numb it. An extremely thin layer of skin is removed (including the tumour) and examined under a microscope. Additional layers of skin are removed if cancer cells are visible. The process is repeated until the samples of skin are cancer-free.

While this is a slow process that often takes several hours, it means that more normal skin can be saved around the tumour. As a result, the area usually looks better after surgery.

• Radiation therapy

Cancer cells are destroyed by x-rays using high energy. There are 2 main types of radiotherapy; external and internal radiotherapy (also known as brachytherapy).¹⁰

Radiation rays are directed at cancer with external beam radiotherapy. It differs from internal radiotherapy, which involves delivering radiation from within the body. External radiotherapy is usually used for skin cancer that is not melanoma. Brachytherapy is an alternative treatment when external radiotherapy is not appropriate. However, this is a rare treatment. 

Non-melanoma skin cancers, including BCC and squamous SCC, can be treated with radiotherapy. It is used to treat:

• A wide area of coverage
• A difficult area of the body to operate
• In cases where surgery results in a poor appearance
• When a person does not wish to have surgery
• When a general anaesthetic isn't appropriate

Radiotherapy might be used after surgery to try and reduce the chance of cancer returning (adjuvant treatment). 

Cancer might also be treated with radiotherapy if it has spread to lymph nodes or another part of the body.

• Chemotherapy

Cancer medicines are often referred to as chemotherapy, or "chemo". Nevertheless, not all drugs used in cancer treatment have the same effects. Chemotherapy is a treatment that kills tumour cells through the use of drugs that are cytotoxic.¹¹

Chemotherapy includes injecting anti-cancer drugs into the vein or taking them orally. The drugs are carried throughout the body through the bloodstream. The chemotherapy can work on cancer cells in lymph nodes and other organs that it has spread to.

These medications are usually administered intravenously (IV) over a few weeks. Several of these medications can slow tumour growth and relieve several symptoms. Some patients may be able to use other treatments, including surgery and radiation therapy, after these treatments have shrunk tumours far enough.

There are side effects associated with chemo drugs, depending on the type, dose, and duration of treatment. Symptoms of chemo may include:¹²

• Hair loss
• Sores on the mouth
• Anorexia
• Feeling nauseated and vomiting
• Constipation or diarrhoea
• A reduced number of white blood cells increases the risk of infection
• The tendency to bruise or bleed easily (due to a lack of blood platelets)
• Tiredness (due to a low level of red blood cells)

After the treatment is over, these side effects usually disappear. 

• Biological therapy

Biological therapy is an approach to treating disease that uses substances derived from living organisms.¹³ These substances may occur naturally in the body or are synthesised in laboratories. Biological therapy helps the body fight cancer by stimulating or suppressing the immune system. 

Biological therapies can be used to attack specific cancer cells, preventing their growth or killing them. They may also lessen some of the side effects associated with certain cancer therapies. 

There are 2 main types of biological therapies; immunotherapy and targeted treatment. For example, immunotherapy includes cancer vaccines, cytokines, and antibodies, as well as some targeted therapies. Biotherapy is also known as biological response modifier therapy.¹⁴

In general, biological therapy is used to treat stage 4 melanoma or cancer that has spread to other parts of the body. Melanoma cells may be genetically tested and the results are used to determine the best biological treatment. 

Biological therapy may also be employed in the case of lymph node involvement with melanoma cells. Therapy used in this way is called adjuvant therapy. 

• Immunotherapy: 

Immunotherapy is a type of biological therapy. It helps the immune system fight cancer cells and involves white blood cells and the lymphatic system. 

Immunotherapy is given in different ways e.g. intravenous, oral, and topical. The dose and duration of immunotherapy depend on the site, type and extent of the cancer.

For skin cancer, melanoma is often treated with immunotherapy drugs called Ipilimumab and Pembrolizumab. Doctors previously treated melanoma with interferon and interleukin 2.¹⁴ 

Immunotherapy also comes with many side effects as a result of a hyperactive immune system. This hyperactivity can lead to the immune system attacking normal cells and tissues as well as the cancer cells. 

Some common side effects of immunotherapy are pain, rash, soreness, and itching at the site of inoculation. It also has flu-like symptoms like fever with chills, weakness, headache, muscle pain, nausea and/or vomiting. Water retention, weight gain, palpitations, and infections are also some systemic side effects.

What is The Best Option for Treatment?

Cancer treatment depends on factors, mainly the type of cancer, site of cancer, age and general health of the patient, and the prognosis and spread of cancer.

The treating doctors take a lot of the above criteria into consideration and then decide on the course of treatment. It is likely that no two patients receive the exact same treatment. The treatment could be a singular type or combination of various therapies. Hence, the treating physician is in the best position to provide the most appropriate treatment for a given patient.

Outlook for Skin Cancer (prognosis)

Like other cancers, early detection and treatment results in better outcomes and survival rates.

In England, almost 100% of people survive melanomas for more than a year after they are diagnosed, 90% survive melanoma for 5 or more years after the diagnosis, and 85% survive their melanomas for 10 or more years after diagnosis.